From: Michal Hocko <mhocko@suse.com>
To: Wei Xu <weixugc@google.com>
Cc: "Yosry Ahmed" <yosryahmed@google.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Johannes Weiner" <hannes@cmpxchg.org>,
"Roman Gushchin" <roman.gushchin@linux.dev>,
"Shakeel Butt" <shakeelb@google.com>,
"Muchun Song" <muchun.song@linux.dev>,
"Ivan Babrou" <ivan@cloudflare.com>, "Tejun Heo" <tj@kernel.org>,
"Michal Koutný" <mkoutny@suse.com>,
"Waiman Long" <longman@redhat.com>,
linux-mm@kvack.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org, "Greg Thelen" <gthelen@google.com>
Subject: Re: [PATCH v4 4/4] mm: memcg: use non-unified stats flushing for userspace reads
Date: Mon, 11 Sep 2023 15:11:41 +0200 [thread overview]
Message-ID: <ZP8SDdjut9VEVpps@dhcp22.suse.cz> (raw)
In-Reply-To: <CAAPL-u9D2b=iF5Lf_cRnKxUfkiEe0AMDTu6yhrUAzX0b6a6rDg@mail.gmail.com>
On Thu 07-09-23 17:52:12, Wei Xu wrote:
[...]
> I tested this patch on a machine with 384 CPUs using a microbenchmark
> that spawns 10K threads, each reading its memory.stat every 100
> milliseconds.
This is rather extreme case but I wouldn't call it utterly insane
though.
> Most of memory.stat reads take 5ms-10ms in kernel, with
> ~5% reads even exceeding 1 second.
Just curious, what would numbers look like if the mutex is removed and
those threads would be condending on the existing spinlock with lock
dropping in place and removed. Would you be willing to give it a shot?
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2023-09-11 13:11 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-31 16:56 [PATCH v4 0/4] memcg: non-unified flushing for userspace stats Yosry Ahmed
2023-08-31 16:56 ` [PATCH v4 1/4] mm: memcg: properly name and document unified stats flushing Yosry Ahmed
2023-09-04 14:44 ` Michal Hocko
2023-09-05 15:55 ` Yosry Ahmed
2023-08-31 16:56 ` [PATCH v4 2/4] mm: memcg: add a helper for non-unified " Yosry Ahmed
2023-09-04 14:45 ` Michal Hocko
2023-08-31 16:56 ` [PATCH v4 3/4] mm: memcg: let non-unified root stats flushes help unified flushes Yosry Ahmed
2023-09-04 14:50 ` Michal Hocko
2023-09-04 15:29 ` Michal Koutný
2023-09-04 15:41 ` Michal Hocko
2023-09-05 14:10 ` Michal Koutný
2023-09-05 15:54 ` Yosry Ahmed
2023-09-05 16:07 ` Michal Koutný
2023-09-12 11:03 ` Michal Hocko
2023-08-31 16:56 ` [PATCH v4 4/4] mm: memcg: use non-unified stats flushing for userspace reads Yosry Ahmed
2023-09-04 15:15 ` Michal Hocko
2023-09-05 15:57 ` Yosry Ahmed
2023-09-08 0:52 ` Wei Xu
2023-09-08 1:02 ` Ivan Babrou
2023-09-08 1:11 ` Yosry Ahmed
2023-09-11 13:11 ` Michal Hocko [this message]
2023-09-11 19:15 ` Wei Xu
2023-09-11 19:34 ` Michal Hocko
2023-09-11 20:01 ` Wei Xu
2023-09-11 20:21 ` Tejun Heo
2023-09-11 20:28 ` Yosry Ahmed
2023-09-12 11:03 ` Michal Hocko
2023-09-12 11:09 ` Yosry Ahmed
2023-08-31 17:18 ` [PATCH v4 0/4] memcg: non-unified flushing for userspace stats Waiman Long
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